Thermostatic switch



May 16, 1933. J w BQHNE 1,909,250

THERMOSTATIC SWI TCH Filed April 4, 1931 Inventor Patented May 16 1933 UNITED STATES JULIUS W. BOHNE, OF STAPLES, MINNESOTA THERMOSTATIG SWITCH Application filed April 4, 1931.

This invention appertains to new and use ful improvements in switches and more particularly to a switch of the thermostatic type.

The principal object of this invention is to provide a thermostatic switch which is both economical to manufacture and durable in use.

Another important object of the invention is to provide a thermostatic switch which can be readily adjusted and which in operation will be positive-acting.

These and other important objects and advantages of the invention will become apparent to the reader of the following specification.

In the drawing Figure 1 represents a top plan view of the switch in an alarm circuit.

Fig. 2 represents a sectional View taken substantially on the line 2-2 of Fig. 1.

Referring to the drawing wherein like numerals designate like parts, it can be seen that numeral 5 represents a base plate upon which the spacer 6 is secured by the screw 7 which screw is disposed thru an opening in the base 5.

The spacer 6 is secured to the bottom side of the thermostatic wafer 8, while the top side of the wafer has a threaded shank extending upwardly therefrom.

A pair of knurled nuts 1011 are engaged on the threaded shank 9 and can be adjusted to various spaced intervals.

Numeral 12 represents a bushing extending through the base plate 5, for insulating the binding post 13 from the base plate. This binding post 13 has a nut 14 thereon and this nut serves to secure the L-shaped arm 15 in place as well as afford a binding post for one side of the alarm circuit 15, which alarm circuit includes the manual switch 16, alarm 17 and source of current 18. The other side of the circuit is connected to the plate 5 as at 19.

It can now be seen, that in the event of a high temperature such as a fire or when used in incubators, or like places, the wafer 8 will expand and result in the engaging of the nut 11, against the arm 15. This will Serial No. 527,785.

complete the circuit 15 and sound the alarm 17 Should it be desired that the alarm also operate when the temperature falls below a certain degree, the nut 10 is properly adjusted, so that when the wafer 8 contracts, the nut 10 will engage the arm 15 and complete the circuit 15.

Obviously, the nuts 10-11 can be readily adjusted on the threaded'shank 9 to meet various conditions.

While the foregoing specification sets forth the invention in specific terms, it is to be understood that numerous changes in the shape, size and materials may be resorted to without departing from the spirit and scope of the invention as claimed hereinafter.

Having thus described my invention, what I claim as new is 2- A thermostatic switch comprising a base plate, a di-electric bushing in the plate, a binding post extending through the bushing and provided with a nut, an L-shaped member having one arm thereof disposed horizontally and the other vertically, said vertical portion being provided with a foot having an opening therein for receiving the post and against which the nut is engageable, the upper free end portion of the L- shaped member being disposed over the base plate, a thermostatic element secured upon the base plate and provided with an upstanding member having a pair of adjustable contacts thereon between which the free end of the L-shaped member is disposed. In testimony whereof I afl'ix my signature.

' JULIUS W. BOHNE. 

